Shaper cutter heads and router bits with indexing feature

ABSTRACT

An apparatus ( 1300 ), including: a shaper cutter head ( 1308 ) having: a body ( 1312 ); a bore ( 1314 ) through the body; and a cutter  1310 ) secured to the body. Along a longitudinal axis ( 1306 ), the cutter has: a miter profile, a groove profile and a tongue profile for cutting a miter. The body has a portion ( 1352 ) comprising a recess ( 1320 ) disposed between the miter profile of the cutter and an end of the body. The recess defines a flat indexing surface ( 1326 ) protruding radially outwards from a portion of the body. When the shaper cutter head is rotated about the longitudinal axis, the body defines a body sweep ( 1360 ). The flat indexing surface is recessed from the body sweep.

FIELD OF THE INVENTION

The invention relates to an indexing feature built into shaper cutterheads and router bits to aid in selecting a cutting height relative to awork surface.

BACKGROUND OF THE INVENTION

Shaper cutter heads and router bits for shaping workpieces are typicallyinstalled in collets of machines that will spin the shaper cutter headsand bits so the shaper cutter heads and bits can shape a workpiece.Router bits usually includes a shank that fits into a collet of themachine. Once the shank is inserted into the collet, the body of themachine can be vertically adjusted. Adjusting the vertical position ofthe body of the machine adjusts a height of a cutter of the bit relativeto a surface on which the workpiece rests. Hence, adjusting the body ofthe machine adjusts a position of the cutter relative to the edge of theworkpiece. Adjusting the position of the cutter enables the operator toproperly align the cutter with the edge of the workpiece. Shaper cutterheads are assembled onto a spindle and the spindle is inserted into acollet of the machine. Vertical adjustment is achieved in a mannersimilar to that of router bits. Certain factors, including varyingthicknesses of the workpieces, make proper alignment difficult. This isespecially true for shaper cutter heads and router bits having cutterprofiles that are free of features that can be used as reference pointsto aid in the alignment of the cutter. Accordingly, there is room in theart for improvement.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in the following description in view of thedrawings:

FIG. 1 is a perspective view of an example embodiment of a router bitwith an example embodiment of an indexing feature;

FIG. 2 is a side view of the router bit of FIG. 1 ;

FIG. 3 is an end view of the router bit of FIG. 1 ;

FIG. 4 is a side view of an alternate example embodiment of a router bitwith example embodiments of the indexing feature;

FIG. 5-9 are side views of various alternate example embodiments of arouter bit with respective example embodiments of the indexing feature;

FIG. 10 is a perspective view of an alternate example embodiment of arouter bit with an example embodiment of the indexing feature;

FIG. 11 is a perspective view of an alternate example embodiment of arouter bit with an example embodiment of the indexing feature;

FIG. 12A is a side view of an example embodiment of a first cooperatingrouter bit with an example embodiment of the indexing feature; and

FIG. 12B is a side view of an example embodiment of a second cooperatingrouter bit with an example embodiment of the indexing feature.

FIG. 13A is a perspective view of an example embodiment of a lock mitershaper head assembly with an example embodiment of an indexing feature.

FIG. 13B is a perspective view of a shaper head of the lock miter shaperhead assembly of FIG. 13A.

FIG. 13C is a perspective view of a shaper spindle of the lock mitershaper head assembly of FIG. 13A.

FIG. 13D is a side view of the shaper head of the lock miter shaper headassembly of FIG. 13A.

FIG. 13E is a closeup of the shaper head of FIG. 13D.

FIG. 13F is a top view of the shaper head of the lock miter shaper headassembly of FIG. 13A.

FIG. 14A is a perspective view of an example embodiment of a concaverouter bit with an example embodiment of an indexing feature.

FIG. 14B and FIG. 14C are side views of the concave router bit of FIG.14A.

FIG. 14D is a top view of the concave router bit of FIG. 14A.

FIG. 15A is a perspective view of an alternate example embodiment of aconcave router bit with an example embodiment of an indexing feature.

FIG. 15B and FIG. 15C are side views of the concave router bit of FIG.15A.

FIG. 15D is a top view of the concave router bit of FIG. 15A.

FIG. 16A is a perspective view of an example embodiment of a concaveshaper head with an example embodiment of an indexing feature.

FIG. 16B is a side view of an example embodiment of the concave shaperhead of FIG. 16A.

FIG. 16C is a top view of an example embodiment of the concave shaperhead of FIG. 16A.

FIG. 17A is a perspective view of an example embodiment of a convexrouter bit with an example embodiment of an indexing feature.

FIG. 17B and FIG. 17C are side views of the convex router bit of FIG.17A.

FIG. 17D is a top view of the convex router bit of FIG. 17A.

FIG. 18A is a perspective view of an example embodiment of a convexshaper head with an example embodiment of an indexing feature.

FIG. 18B is a side view of an example embodiment of the convex shaperhead of FIG. 18A.

FIG. 18C is a top view of an example embodiment of the convex shaperhead of FIG. 18A.

DETAILED DESCRIPTION OF THE INVENTION

The present inventor has created unique and innovative router bits andshaper heads with an indexing feature that enables accurate alignment ofa cutter of the router bit or shaper head with an edge of a workpiece.The indexing feature provides a reference point on the router bit thatcan be used to position the cutter of the router bit or shaper headrelative to a work surface. A workpiece will rest on the work surfaceduring a routing operation. As such, positioning the indexing featurerelative to the work surface naturally positions the indexing feature,and hence the cutter, relative to the workpiece.

Workpieces often vary in thickness throughout the workpiece and from oneworkpiece to another workpiece. As a result, router bits or shaper headsare often set up by aligning the center of the cutter with a midpoint ofthe workpiece being routed. As used herein, the center of the cutter isthe axial center relative to a longitudinal axis of the shank of therouter bit, between bitter ends of the cutter. The cutter is the part ofthe router bit or shaper head having an edge that is a cutting edge. Inthe example embodiments disclosed herein, the machine is a router orshaper, however, the principles disclosed herein may be used with othermachines. Since the workpiece will rest on a work surface when beingrouted or shaped, one simply needs to vertically position the body ofthe router or shaper head so that the center of the cutter coincideswith the center of the workpiece when the workpiece is on the worksurface. To do this, one determines the thickness of the workpiece anddivides that in half to get a “half thickness.” The body of the routeror shaper head is then vertically adjusted so that the center of thecutter is disposed at a distance that puts it the half thickness abovethe work surface. When the workpiece is placed on the work surface, themidpoint of the workpiece will then coincide with the center of thecutter.

However, some cutters have a profile that does not have a discernablefeature at the center that can be used as a reference point. Sometimes,for example, the cutter profile is smooth and angled (not perpendicularto the longitudinal axis) at the center of the cutter. Without adiscernible reference point, proper alignment of the cutter is difficultand may require a hit or miss approach until the proper position isreached. The router bits or shaper heads disclosed herein have anindexing feature built into the router bit or shaper head at a locationother than the cutter itself such as the shank or a body of the routerwhich secures the cutter to the shank, or a body of a shaper head. Theindexing feature can be used to position the cutter relative to the worksurface and thereby properly align the cutter with the workpiece.

In example embodiments used herein, the indexing feature is located atthe midpoint of the cutter. This simplifies the explanation because themidpoint of the cutter naturally coincides with the half thickness ofthe workpiece. However, the indexing feature can be located at any pointbetween and including the bitter ends of the cutter. Stated another way,the indexing feature may be at a location that is offset from the axialcenter by an offset amount. If the offset is known, then the referencefeature should be positioned at a distance from the work surface that isthe half thickness plus (or minus) the offset. For example, the offsetfrom the center of the cutter is 0.1″ (toward the base of the shank thatgoes into the collet). If the half thickness of the workpiece is onehalf (½) an inch, the indexing feature will be located at 0.4″ (the halfthickness minus the offset) above the work surface. Hence, whileembodiments discussed below place the indexing feature at the center ofthe cutter, the indexing feature can be at any location along thecutter. This allows for positioning of the indexing feature at alternatelocations when, for example, it is relatively difficult or impossible toplace the indexing feature at the center.

FIG. 1 to FIG. 3 show an example embodiment of a router bit with anexample embodiment of an indexing feature. The router bit 100 includes ashank 104 that defines a longitudinal axis 106, a cutter 110, and a body112 that secures the cutter 110 to the shank 104. It is noted that thecutters 110 in the example embodiments of FIG. 1 to FIG. 3 areidentical, though this need not be the case. When spun about thelongitudinal axis 106, the body 112 defines a sweep 114. As used herein,a sweep is a (hollow) shape made by a radially outer boundary of theobject making the sweep. As best seen in FIG. 2 , a recess 120 islocally recessed into the body 112 relative to the sweep 114 of the body112. The recess 120 is disposed between a collet bitter end 122 of thecutter 110 and a tip bitter end 124 of the cutter 110 and comprises anindexing feature 126. It should be noted that the sweep of the body 112is set back from an edge and corresponding sweep (not shown) of thecutter 110. This is because the radial outer boundary of the cutter 110is naturally radially farther out than that of the body 112. As can bebest seen in FIG. 3 , there may be more than one recess 120 andassociated indexing feature 126. This may, for example, provide bettersymmetry and associated balance to the router bit 100. However, symmetryis not necessary. Instead, there may be one, or any number more than oneof the indexing features 126.

In this example embodiment, the indexing feature 126 is embodied as aflat surface 130 oriented perpendicular to the longitudinal axis 106.Since it is perpendicular to the longitudinal axis 106, a normal 132 ofthe flat surface 130 is parallel to the longitudinal axis 106. A flatsurface 130 is suitable as a reference surface for gauges that aremeasuring from the work surface because the gauge can land on any partof the flat surface 130 and still get the same distance measurement.

In the example embodiment shown, a proximal end 140 of the router bit100 is configured to be inserted into a router, and the flat surface 130faces a distal end 142 of the router bit 100 that is opposite theproximal end 140. As best seen in FIG. 2 , the indexing feature 126 islocated at a midpoint 150 (D/2, a.k.a. the center) between collet bitterend 122 of the cutter 110 and a tip bitter end 124 of the cutter 110. Inthis example embodiment, the router bit 100 is configured to cut a lockmiter joint, but other router bits may be used.

As noted above, the recess 120 may be located at a non-zero offset fromthe midpoint 150. Moreover, the indexing feature 126 may be differentthan a flat surface (e.g., a corner) as is detailed below. The indexingfeature 126 may alternately axially coincide with a feature of a sweepformed by the cutter profile such as an inflection point etc. as isdetailed below.

FIG. 4 is a side view of an alternate example embodiment of a router bitwith example embodiments of the indexing feature. The router bit 400includes a shank 404 that defines a longitudinal axis 406, a cutter 410,a body 412 that secures the cutter 410 to the shank 404, a collet bitterend 422 of the cutter 410, a tip bitter end 424 of the cutter 410, aproximal end (not visible) of the router bit 400, and a distal end 442of the router bit 400 that is opposite the proximal end 440.

A first recess 420 includes an indexing feature 426 embodied as a corner430 of the first recess 420 and disposed at the midpoint 450 (D/2,a.k.a. the center) between collet bitter end 422 of the cutter 110 and atip bitter end 424 of the cutter 410. The first recess 420 is recessedboth from a sweep 414A of the body 412 and recessed from a local surface416 of the body 412 surrounding the first recess 420. An indexingfeature 426 embodied as a corner is suitable for a gauge with a pointedpointer. The pointed pointer may interlock/cooperate with the corner 430so the router bit 400 can be accurately positioned.

A second recess 460 includes an indexing feature 462 embodied as a flatsurface 464. The second recess 460 is recessed both from a sweep 4148 ofthe body 412 and recessed from a local surface 466 of the body 412surrounding the first recess 420. The second recess 460 is disposed atan offset 468 from the midpoint 450 (D/2, a.k.a. the center) betweencollet bitter end 422 of the cutter 110 and a tip bitter end 424 of thecutter 410. As this example embodiment shows, there may be more than oneindexing feature on a router bit, they may be at the same or differentaxial locations, and they may have the same or different shapes.Further, the indexing features may be at different radial distances fromthe longitudinal axes 406.

FIG. 5 to FIG. 9 show various example embodiments a router bit withexample embodiments of the indexing feature. In these exampleembodiments, the router bit is configured to cut a butterfly shape, butthe indexing features can be used with router bits configured to cutother shapes. The principles are discussed in depth with respect to FIG.5 and apply to FIG. 5 to FIG. 9 . The router bit 500 includes a shank504 that defines a longitudinal axis 506, a cutter 510, a body 512 thatsecures the cutter 510 to the shank 504, a collet bitter end 522 of thecutter 510, a tip bitter end 524 of the cutter 510, a proximal end 540of the router bit 500, and a distal end 542 of the router bit 500 thatis opposite the proximal end 540.

As shown in FIG. 5 ., the cutter 510 defines a cutter sweep 570 (shownunder a dotted line) when the router bit 500 a spun about thelongitudinal axis 506. A design setback sweep 572 (shown under thedotted line) is set back by a setback 574 from the cutter sweep 570 andextends from one bitter end of the body 512 to the other bitter end ofthe body 512. The design setback sweep 572 follows a profile of thecutter sweep 570. The setback 574 may be the same amount or may vary indifferent sections of the design setback sweep 572. The design setbacksweep 572 defines a body sweep of conventional router bodies. In otherwords, the radially outermost portion of the body of a conventionalrouter bit follows the design setback sweep 572. The radially outermostportion of the body is that portion shown in FIG. 5 closest to a cuttingedge of the cutter 510. As used herein, follows can mean that for everyfeature in the shape of the cutter sweep 570 there is a correspondingfeature in the shape of the design setback sweep 572, even if therelationship includes a variation in the magnitude of the setback 574.Likewise, for every feature in the shape of the design setback sweep572, there is a feature corresponding feature in the shape of the cuttersweep 570.

As shown in FIG. 5 , the cutter 510 rotates into the page on the rightside as shown by arrow tail 580. Upon half a rotation the cutter 510would be rotating out of the page on the left side as shown by arrowhead582. The radially outermost portion of the body 512 (shown under thedotted/dashed lines) is disposed on a back/support side 584 of thecutter 510 that is opposite a cutting face (not visible) of the cutter510. The radially outermost portion of the body 512 exists to providesupport to the cutter 510 as the cutter 510 cuts the workpiece. The restof the body 512 may or may not taper radially inward withcircumferential distance toward the cutter face 586 of a second cutter588. In the example embodiment shown in FIG. 5 , the body 512 does taperradially inward. This creates a larger setback 576 at the cutter face586 of the second cutter 588 which helps ensure the body 512 is clearmaterial being removed from the workpiece. It is noted that the cutters510, 588 in the example embodiments of FIG. 5 to FIG. 9 are identical,though this need not be the case.

Unlike conventional router bits where the body sweep is controlled by(e.g., follows) the design setback sweep 572, in this exampleembodiment, the body sweep 514 includes a recess 520 locally recessedinto the body 512 from the design setback sweep 572 in a portion 592 ofthe design setback sweep 572. Stated another way, unlike conventionalrouter bits, the body sweep 514 in this example embodiment does notfollow the entire design setback sweep 572. Instead, the body sweep 514locally deviates from the design setback sweep 572 in portion 592 of thedesign setback sweep 572. In other words, the body sweep 514 includes atleast one feature for which there is no corresponding feature in thecutter sweep 570.

The recess 520 includes the indexing feature 526. In the exampleembodiment shown in FIG. 5 , the indexing feature 526 includes a flatsurface 530 like the flat surface 130 of FIG. 1 to FIG. 3 that isperpendicular to the longitudinal axis 506 and that faces the distal end542 of the router bit 500. In this example embodiment, the indexingfeature 526 is located at the midpoint 550 between the proximal end 540of the router bit 500, and the distal end 542 of the router bit 500.However, any location along the longitudinal axis 506 would suffice. Thecutter 510 includes an inflection point 594 (e.g., a point/peak) at themidpoint 550, so the indexing feature 526 is coaxially located with theinflection point 594.

In a conventional router bit, since the body and body sweep follow thedesign setback sweep 572, the body sweep would have a point at themidpoint 550 that matches the point on the design setback sweep 572 andthereby the point on the cutter 510. However, as can be seen in FIG. 5 ,the body 512 and body sweep 514 have a point that is different from thepoint on the design setback sweep 572 and thereby the cutter 510.Specifically, the angle that defines the point on the body sweep 514 ishalf the angle that defines the point on the design setback sweep 572and thereby the cutter 510. At the location of the indexing feature, theshape of the body sweep 514 is thereby naturally different than theshape of the design setback sweep 572, the cutter sweep 570, and thecutter 510.

FIG. 6 shows an alternate example embodiment of a router bit 600 with arecess 620 and an indexing feature 626 embodied as a flat surface 630.The recess 620 of this example embodiment is recessed relative to thedesign setback sweep 672 and extends to the second cutter 688 similar tothat of the example embodiment of FIG. 5 . The flat surface 630 isperpendicular to the longitudinal axis 606, but in this exampleembodiment, the flat surface 630 faces toward the proximal end 640 ofthe router bit 600.

FIG. 7 shows an alternate example embodiment of a router bit 700 with arecess 720 and an indexing feature 726 embodied as a flat surface 730.The recess 720 of this example embodiment is recessed both relative tothe design setback sweep 772 and locally relative to a local surface 716of the body 712 surrounding the recess 720. The flat surface 730 isperpendicular to the longitudinal axis 706 and faces toward the distalend 742 (away from the proximal end 740) of the router bit 700. Therecess 720 of this example embodiment does not extend all the way to thesecond cutter 788.

FIG. 8 shows an alternate example embodiment of a router bit 800 with alongitudinal axis 806 and a proximal end 840. The router bit 800 has arecess 820 that opens radially outward and an indexing feature 826embodied as a corner 830. The recess 820 of this example embodiment isrecessed both relative to the design setback sweep 872 and locallyrelative to a local surface 816 of the body 812 surrounding the recess820.

FIG. 9 shows an alternate example embodiment of a router bit 900 with alongitudinal axis 906 and a proximal end 940. The router bit 900 has arecess 920 that opens radially outward and an indexing feature 926embodied as a curved surface 930. The recess 920 of this exampleembodiment is recessed both relative to the design setback sweep 972 andlocally relative to a local surface 916 of the body 912 surrounding therecess 920. In this example embodiment, the indexing feature 926 isconfigured to cooperate with pointer of a measuring tool. Suchcooperation aligns the pointer with the indexing feature by, forexample, geometric cooperation therebetween. For example, the pointermay be shaped in a mirror/reverse shape of the indexing feature 926 sothat the pointer has a convex surface that nests into the indexingfeature 926. When the intended nesting is reached, the pointer isproperly aligned with the indexing feature 926.

While the indexing feature 926 in this example embodiment has a concavecurved shape, any shape can be used so long as a suitably shaped pointercan cooperatively interact with the indexing feature 926 to result inthe proper alignment therebetween. Further, the pointer need not havethe exact same shape as the indexing feature 926 to achieve the properalignment. For example, the indexing feature 926 could be in the shapeof a V-groove (e.g., FIG. 8 ) or have three sides of a square and thepointer could be shaped like a sphere and properly cooperate/fit thereinto achieve the proper alignment.

FIG. 10 shows an alternate example embodiment of a router bit 1000 witha recess 1020 and an indexing feature 1026 embodied as a flat surface1030. The recess 1020 of this example embodiment is recessed relative tothe design setback sweep 1072 and extends from the cutter 1010 to thesecond cutter 1088. The design setback sweep 1072 is shown here at thedownstream/other end of the recess 1020 instead of at the cutter 1010.This is because in this example embodiment the body 1012 does not taperradially inward toward the second cutter 1088. As such, at a givenlocation relative to the longitudinal axis 1006, the radially outer edgeof the body 1012 remains at the same radial distance from thelongitudinal axis 1006. The flat surface 1030 is perpendicular to thelongitudinal axis 1006 and faces toward the distal end 1042 of therouter bit 1000. The location of the indexing feature 1026 coincideswith the location of an inflection point 1094 of a curve in the cutter1010 and associated sweep formed by the cutter relative to thelongitudinal axis 1006. It is noted that the cutters 1010, 1088 areidentical in this example embodiment, so the inflection point 1094 onthe second cutter 1088 coincides with a same inflection point on thecutter 1010.

FIG. 11 shows an alternate example embodiment of a router bit 1100 witha recess 1120 that opens radially outward and an indexing feature 1126embodied as a corner 1130. The recess 1120 of this example embodiment isrecessed locally relative to the local surface 1116 of the body 1112surrounding the recess 1120. The router bit 1100 has a first cutter/bodyarrangement 1130 with the cutter 1110 and the body 1112, and a secondcutter/body arrangement 1132 having a second cutter 1134 and a secondbody 1136. The first cutter/body arrangement 1130 and the secondcutter/body arrangement 1132 are discrete each other. The firstcutter/body arrangement 1130 and the second cutter/body arrangement 1132occupy discrete portions of the length of the router bit 1100 along thelongitudinal axis 1106 and are separated by a bearing 1140 configured toroll on an edge of the workpiece between portions of the workpiece beingrouted. The location of the indexing feature 1126 can be selected to bea midpoint between bitter ends of the cutter 1110, or a midpoint with anoffset as detailed above.

Alternately, the location of the indexing feature 1126 can be selectedto be a midpoint between the collet bitter end 1122 of the cutter 1110and a tip bitter end 1142 of the second cutter 1134. Likewise, thelocation of the indexing feature 1126 can be selected to be the midpointbetween the collet bitter end 1122 of the cutter 1110 and the tip bitterend 1142 of the second cutter 1134 with an offset. The latter may besuitable in instances like that shown in FIG. 11 , where it may bedifficult or impossible to locate the indexing feature 1126 at themidpoint of both cutters 1110, 1142 due to the presence of the bearing1140 or the like. Considering all the cutters on the router bit whenchoosing the location of the indexing feature 1126 allows for indexingrelative to the entire cutting sweep/profile of the router bit 1100instead of the cutting sweep/profile of one cutter of the router bit1100.

In the embodiment shown in FIG. 11 , the cutter 1110 is one of twocutters in the first cutter/body arrangement 1130. The two cutters areidentical and hence interchangeable as used to this point. The sameapplies to the cutters of the second cutter/body arrangement 1132.However, it is possible that a single cutter/body arrangement can havetwo or more different cutters attached to the same body. For example,the different cutters may have different shapes at different axiallocations. Alternately, or in addition, the different cutters may havedifferent shapes but be at the same or overlapping axial positions. Sucha cutter arrangement includes progressive cutters where each cutter cutsonly a portion of the final profile that the router bit as a whole cuts.Applying the principles detailed above, the indexing feature can belocated relative to the midpoint (with or without an offset) of any oneof the cutters, relative to the midpoint (with or without an offset) ofany combination of the cutters, and/or relative to the midpoint (with orwithout an offset) of all of the cutters taken as a whole.

FIGS. 12A and 12B collectively depict the operation of a first routerbit 1200A and a cooperating second router bit 1200B to form a singleedge profile 1202 in a workpiece 1204. The first router bit 1200Adefines a first cutter sweep 1210A from the collet bitter end 1212A to areference location 1214A. The first cutter sweep 1210A routs a firsthalf 1220A of the edge profile 1202 in the edge of the workpiece 1204.

The second router bit 1200B defines a second cutter sweep 1210B from thecollet bitter end 1212B to a reference location 1214B. The second cuttersweep 1210B routs a second half 1220B of the edge profile 1202 in theedge of the workpiece 1204. A workpiece reference point 1222 isestablished in the edge profile 1202 to coincide with the referencelocation 1214A in the first router bit 1200A and the reference location1214B in the second router bit 1200B.

The workpiece reference point 1222 may be expected to be at a particularlocation within the thickness of the workpiece 1204, (e.g., themidpoint, the ⅓ mark, the ¼ mark etc.). The reference location 1214Amust be aligned with the workpiece reference point 1222 (e.g., themidpoint, the half thickness) before the first half 1220A can be routed.Then, to rout the second half 1220B, the reference location 1214B of thesecond router bit 1200B must be aligned with the workpiece referencepoint 1222, after which the second half 1220B can be routed. Suchalignments can be tedious, difficult, and/or a hit or miss process.

In the example embodiment of FIGS. 12A and 12B, a recess 1230A having anindexing feature 1232A embodied as a flat surface that is perpendicularto the longitudinal axis 1234A is formed in the body 1236A. The recess1230A of this example embodiment is recessed relative to the designsetback sweep. The indexing feature 1232A is collocated with thereference location 1214A relative to the longitudinal axis 1234A.Accordingly, to align the first router bit 1200A, the half thickness ofthe workpiece 1204 is determined, and the indexing feature 1232A ismerely located at a distance that corresponds to the half thickness fromthe work surface 1240. Once this is done, the first half 1220A can berouted.

Likewise, a recess 12308 having an indexing feature 12328 embodied as aflat surface that is perpendicular to the longitudinal axis 12348 isformed in the body 12368. The recess 12308 of this example embodiment isrecessed relative to the design setback sweep. The indexing feature12328 is collocated with the reference location 12148 relative to thelongitudinal axis 12348. To align the second router bit 12008, the halfthickness of the workpiece 1204 is determined, and the indexing feature12328 is merely located at a distance that corresponds to the halfthickness from the work surface 1240. Once this is done, the workpiece1204 is flipped over and the second half 1220B can be routed.

As detailed above, the indexing features 1232A, 12328 can be located atthe midpoint or at the midpoint plus an offset. Hence, the indexingfeatures 1232A, 12328 can be configured to associate with any workpiecereference point 1222, regardless of where in the thickness of theworkpiece the workpiece reference point 1222 is located.

Although the disclosure to this point has related to router bits, thisentire disclosure also applies to shaper heads and shaper headassemblies used in woodworking shaper machines. A shaper assemblygenerates the same type of cut as its counterpart router bit, albeitusing a two-piece assembly. Roter bits and shaper cutter heads arecollectively referred to herein as cutting bits.

FIG. 13A to FIG. 13F are various views of an example embodiment of alock miter shaper head assembly 1300 and components thereof with anindexing feature 1326. The shaper head assembly 1300 includes a shapercutter head 1308 and a shaper spindle 1304. The shaper head assembly1300 generates the same type of cut as the lock miter router bit of FIG.1 and operates using the same principles, mutatis mutandis. The shaperspindle 1304 is suitable for use with all shaper heads disclosed herein.

The shaper cutter head 1308 includes multiple cutters 1310 secured to ashaper body 1312; a bore 1314 through the body. While multiple cutters1310 are shown, there only needs to be one cutter 1310. If multiplecutters are used, where each cutter occupies a different space along thelongitudinal axis, then the cutter proximal axial end is the proximalend of the most proximal cutter and the cutter distal end is the distalend of the most distal cutter.

The shaper body 1312 is configured to be releasably secured to via thebore 1314 to the shaper spindle 1304 and when so assembled the shaperbody 1312 and the cutters 1316 extend along a longitudinal axis 1330(e.g., axis of rotation) defined by the shaper spindle 1304.

The shaper body 1312 includes a body proximal end 1340, a body distalend 1342, and further includes multiple recesses 1320 that each define arespective indexing feature 1326 and a respective normal line 1332extending therefrom. While multiple recesses 1320 are shown, there onlyneeds to be one recess 1320. The indexing feature 1326 is a flat surfacethat extends perpendicular to the longitudinal axis 1306 such that thenormal line 1332 to the flat surface extends parallel to thelongitudinal axis 1330. The flat surface indexing feature 1326 islocated at a midpoint 1328 (D/2, a.k.a. the exact center) between thecutter distal end 1324 and the cutter proximal end 1322.

Each cutter 1316 includes a cutting edge 1316C having a cutter proximalend 1322 and a cutter distal end 1324. The cutter 1316 defines a miterprofile 1338 that includes a groove-cutting portion 1338G and atongue-cutting portion 1338T.

When spun about the longitudinal axis 1306, the shaper body 1312 definesa body sweep 1360. The outer periphery of the body sweep 1360 isindicated by a dashed path 1360P in FIG. 13D and FIG. 13E. As seen inFIG. 13D and FIG. 13E, the outer periphery forms a path that starts atthe body distal end 1342, ends at the body proximal end 1344, forms acontinuous path along the periphery of the shaper body 1312, and lieswithin a radial plane that is parallel to the longitudinal axis 1306(i.e., parallel to the page in FIG. 13D). The path 1360P extends axiallyand radially but not circumferentially relative to the longitudinal axis1330 and connects radiuses R1, R2, R3A, R3B, R4A, R4B, R5, and R6. R3Aand R3B are collectively R3. R4A and R4B are collectively R4. Of these,radiuses R1, R2, R3A, R5, and R6 are visible and indicated with dashedlines in FIG. 13E.

As can be seen in the top view of FIG. 13E, the flat surface indexingfeature 1326 protrudes radially outward in relation to at least aportion of the shaper body 1312. As is also visible in FIG. 13E, theflat surface indexing feature 1326 exists in a radial location that isbetween R1 and R3. In the embodiment shown, the flat surface indexingfeature 1326 exists on both radial sides of R2 but could exists on onlyone radial side of R2 but not the other radial side.

As can be seen in the left side of the side view of FIG. 13D, the recess1320 and the flat surface indexing feature 1326 are both locallyrecessed relative to the body sweep 1360. As is also visible in FIG.13D, the shaper body 1312 comprises a substantially fructo-conical firstportion 1350 disposed closer to the body distal end 1342, a centralportion 1352 adjacent the groove-cutting portion 1338G and thetongue-cutting portion 1338T, and a second portion 1354 closer to thebody proximal end 1344.

The shaper spindle 1304 includes a threaded rod 1304R, various spacers1304A, 1304B, 1304C, 1304D, and a nut 1304N to secure the shaper headassembly 1300 together once the shaper cutter head 1308 is installedthereon.

FIG. 14A to FIG. 14D are various views of an example embodiment of aconcave router bit 1400 with an example embodiment of an indexingfeature 1426. In this example embodiment, the concave router bit 1400 isa round over bit.

The concave router bit 1400 includes a shank 1404 that defines alongitudinal axis 1406, multiple cutters 1410, a body 1412 that securesthe cutters 1410 to the shank 1404, recesses 1420, a cutter proximal end1422, a cutter distal end 1424, the indexing features 1426, a bodyproximal end 1440, and a body distal end 1442 that is opposite the bodyproximal end 1440. While multiple cutters 1410 are shown, there onlyneeds to be one cutter 1410. While multiple recesses 1420 are shown,there only needs to be one recess 1420.

The indexing feature 1426 is a flat surface that extends perpendicularto the longitudinal axis 1406 such that the normal line 1432 to the flatsurface extends parallel to the longitudinal axis 1406. The flat surfaceindexing feature 1426 is located at a midpoint 1428 (D/2, a.k.a. theexact center) between the cutter proximal end 1422 and the cutter distalend 1424.

Along the longitudinal axis 1406 the cutter 1410 defines a concavecutting-edge profile 1490. In this example embodiment, the concavecutting-edge profile 1490 defines an arcuate shape that forms asemi-circle, although any concave shape is possible. The concavecutting-edge profile 1490 is symmetric about a midpoint 1492 of theconcave cutting-edge profile 1490. As shown in FIG. 14B, symmetric aboutthe midpoint 1492 means that the part of the concave cutting-edgeprofile 1490 above the midpoint 1492 is a mirror image of a part of theconcave cutting-edge profile 1490 below the midpoint 1492. However, theconcave cutting-edge profile 1490 need not be symmetric about themidpoint 1492.

The midpoint 1492 is a point that is equidistant along the longitudinalaxis 1406 from the cutter proximal end 1422 and the cutter distal end1424 (the longitudinal ends of the concave cutting-edge profile 1490).The midpoint 1492 also coincides with a turning point 1994 of theconcave cutting-edge profile 1490, which is a point at which the profileturns along the horizontal axis as seen in FIG. 14B. The turning point1494 of the concave cutting-edge profile 1490 is also a radiallyinnermost point of the concave cutting-edge profile 1490 relative to thelongitudinal axis 1406. In this example embodiment, the midpoint 1492,the turning point 1494, and the flat surface indexing feature 1426 allcoexist at the midpoint 1428 (D/2, a.k.a. the exact center) between thecutter proximal end 1422 and the cutter distal end 1424.

The body 1412 likewise defines a concave body profile 1496. In thisexample embodiment, the concave body profile 1496 defines an arcuateshape that forms a semi-circle, although any shape is possible. Theconcave body profile 1496 is uninterrupted except for a lone subregion1498 defined by the recess 1420. The flat surface indexing feature 1426bisects the concave cutting-edge profile 1490 and the concave bodyprofile 1496. Along the longitudinal axis 1406, a profile of the recess1420 is asymmetric about the midpoint 1492. As shown in FIG. 14B,asymmetric about the midpoint 1492 means that the part of the profile ofthe recess 1420 above the midpoint 1492 is not a mirror image of a partof the profile of the recess 1420 below the midpoint 1492. In thisexample embodiment, the part that is not symmetric is limited to thesubregion 1498.

FIG. 15A to FIG. 15D are various views of an alternate exampleembodiment of a concave router bit 1500 with an example embodiment of anindexing feature 1526. In this example embodiment, the concave routerbit 1500 is a thumbnail bit.

The concave router bit 1500 includes a shank 1504 that defines alongitudinal axis 1506, multiple cutters 1510, a body 1512 that securesthe cutters 1510 to the shank 1504, recesses 1520, a cutter proximal end1522, a cutter distal end 1524, the indexing features 1526, a bodyproximal end 1540, and a body distal end 1542 that is opposite the bodyproximal end 1540.

The indexing feature 1526 is a flat surface that extends perpendicularto the longitudinal axis 1506 such that the normal line 1532 to the flatsurface extends parallel to the longitudinal axis 1506. The flat surfaceindexing feature 1526 is located at a midpoint 1528 (D/2, a.k.a. theexact center) between the cutter proximal end 1522 and the cutter distalend 1524.

Along the longitudinal axis 1506 the cutter 1510 defines a concavecutting-edge profile 1590. In this example embodiment, the concavecutting-edge profile 1590 defines an arcuate shape that forms a minorcircular arc, although any concave shape is possible. The concavecutting-edge profile 1590 is symmetric about a midpoint 1592 of theconcave cutting-edge profile 1590. As shown in FIG. 15B, symmetric aboutthe midpoint 1592 means that the part of the concave cutting-edgeprofile 1590 above the midpoint 1592 is a mirror image of a part of theconcave cutting-edge profile 1590 below the midpoint 1592. However, theconcave cutting-edge profile 1590 need not be symmetric about themidpoint 1592.

The midpoint 1592 is a point that is equidistant along the longitudinalaxis 1506 from the cutter proximal end 1522 and from the cutter distalend 1524 (the longitudinal ends of the concave cutting-edge profile1590). The midpoint 1592 also coincides with a turning point 1994 of theconcave cutting-edge profile 1590, which is a point at which the profileturns along the horizontal axis as seen in FIG. 15B. The turning point1594 of the concave cutting-edge profile 1590 is also a radiallyinnermost point of the concave cutting-edge profile 1590 relative to thelongitudinal axis 1506. In this example embodiment, the midpoint 1592,the turning point 1594, and the flat surface indexing feature 1526 allcoexist at the midpoint 1528 (D/2, a.k.a. the exact center) between thecutter proximal end 1522 and the cutter distal end 1524.

The body 1512 likewise defines a concave body profile 1596. In thisexample embodiment, the concave body profile 1596 defines an arcuateshape that forms a semi-circle, although any shape is possible. Theconcave body profile 1596 is uninterrupted except for a lone subregion1598 defined by the recess 1520. The flat surface indexing feature 1526bisects the concave cutting-edge profile 1590 and the concave bodyprofile 1596. Along the longitudinal axis 1506, a profile of the recess1520 is asymmetric about the midpoint 1592. As shown in FIG. 15B,asymmetric about the midpoint 1592 means that the part of the profile ofthe recess 1520 above the midpoint 1592 is not a mirror image of a partof the profile of the recess 1520 below the midpoint 1592. In thisexample embodiment, the part that is not symmetric is limited to thesubregion 1598.

FIG. 16A to FIG. 16C are various views of an example embodiment of aconcave shaper head 1608 with an example embodiment of an indexingfeature 1626. In this example embodiment, the concave shaper head 1608is a round over shaper head. The concave shaper head 1608 generates thesame type of cut as the round over router bit of FIG. 14A and operatesusing the same principles, mutatis mutandis. However, any concave shapeis possible. The concave shaper head 1608 is suitable for use with ashaper spindle 1304 like that shown in FIG. 13C to form a shaper headassembly.

The concave shaper head 1608 defines a longitudinal axis 1606 that whenassembled to the shaper spindle 1304 is the same as the longitudinalaxis 1306 of the shaper spindle 1304. The concave shaper head 1608includes multiple cutters 1610, a body 1612, a bore 1614 to secure thecutters 1610 to the shaper spindle 1304, multiple recesses 1620, acutter proximal end 1622, a cutter distal end 1624, the indexingfeatures 1626, a body proximal end 1640, and a body distal end 1642 thatis opposite the body proximal end 1640. While multiple cutters 1610 areshown, there only needs to be one cutter 1610. Likewise, while multiplerecesses 1620 are shown, there only needs to be one recesses 1620. Ifmultiple cutters are used, where each cutter occupies a different spacealong the longitudinal axis, then the cutter proximal axial end is theproximal end of the most proximal cutter and the cutter distal end isthe distal end of the most distal cutter.

The indexing feature 1626 is a flat surface that extends perpendicularto the longitudinal axis 1606 such that the normal line 1632 to the flatsurface extends parallel to the longitudinal axis 1606. The flat surfaceindexing feature 1626 is located at a midpoint 1628 (D/2, a.k.a. theexact center) between the cutter proximal end 1622 and the cutter distalend 1624.

Along the longitudinal axis 1606 the cutter 1610 defines a concavecutting-edge profile 1690. In this example embodiment, the concavecutting-edge profile 1690 defines an arcuate shape that forms asemicircle, although any concave shape is possible. The concavecutting-edge profile 1690 is symmetric about a midpoint 1692 of theconcave cutting-edge profile 1690. As shown in FIG. 16B, symmetric aboutthe midpoint 1692 means that the part of the concave cutting-edgeprofile 1690 above the midpoint 1692 is a mirror image of a part of theconcave cutting-edge profile 1690 below the midpoint 1692. However, theconcave cutting-edge profile 1690 need not be symmetric about themidpoint 1692.

The midpoint 1692 is a point that is equidistant along the longitudinalaxis 1606 from the cutter proximal end 1622 and from the cutter distalend 1624 (the longitudinal ends of the concave cutting-edge profile1690). The midpoint 1692 also coincides with a turning point 1994 of theconcave cutting-edge profile 1690, which is a point at which the profileturns along the horizontal axis as seen in FIG. 16B. The turning point1694 of the concave cutting-edge profile 1690 is also a radiallyinnermost point of the concave cutting-edge profile 1690 relative to thelongitudinal axis 1606. In this example embodiment, the midpoint 1692,the turning point 1694, and the flat surface indexing feature 1626 allcoexist at the midpoint 1628 (D/2, a.k.a. the exact center) between thecutter proximal end 1622 and the cutter distal end 1624.

The body 1612 likewise defines a concave body profile 1696. In thisexample embodiment, the concave body profile 1696 defines an arcuateshape that forms a semi-circle, although any shape is possible. Theconcave body profile 1696 is uninterrupted except for a lone subregion1698 defined by the recess 1620. The flat surface indexing feature 1626bisects the concave cutting-edge profile 1690 and the concave bodyprofile 1696. Along the longitudinal axis 1606, a profile of the recess1620 is asymmetric about the midpoint 1692. As shown in FIG. 16B,asymmetric about the midpoint 1692 means that the part of the profile ofthe recess 1620 above the midpoint 1692 is not a mirror image of a partof the profile of the recess 1620 below the midpoint 1692. In thisexample embodiment, the part that is not symmetric is limited to thesubregion 1698.

FIG. 17A to FIG. 17D are various views of an example embodiment of aconvex router bit 1700 with an example embodiment of an indexing feature1726.

The convex router bit 1700 includes a shank 1704 that defines alongitudinal axis 1706, multiple cutters 1710, a body 1712 that securesthe cutters 1710 to the shank 1704, recesses 1720, a cutter proximal end1722, a cutter distal end 1724, the indexing features 1726, a bodyproximal end 1740, and a body distal end 1742 that is opposite the bodyproximal end 1740. In this example embodiment, the shank 1704 includes abolt 1704A, a washer 1704B, and a bearing 1704C that releasable securethe body 1712 to the shank 1704.

The indexing feature 1726 is a flat surface that extends perpendicularto the longitudinal axis 1706 such that the normal line 1732 to the flatsurface extends parallel to the longitudinal axis 1706. The flat surfaceindexing feature 1726 is located at a midpoint 1728 (D/2, a.k.a. theexact center) between the cutter proximal end 1722 and the cutter distalend 1724.

Along the longitudinal axis 1706 the cutter 1710 defines a convexcutting-edge profile 1790. In this example embodiment, the convexcutting-edge profile 1790 defines an arcuate shape that forms a minorcircular arc, although any convex shape is possible. The convexcutting-edge profile 1790 is symmetric about a midpoint 1792 of theconvex cutting-edge profile 1790. As shown in FIG. 17B, symmetric aboutthe midpoint 1792 means that the part of the convex cutting-edge profile1790 above the midpoint 1792 is a mirror image of a part of the convexcutting-edge profile 1790 below the midpoint 1792. However, the convexcutting-edge profile 1790 need not be symmetric about the midpoint 1792.

The midpoint 1792 is a point that is equidistant along the longitudinalaxis 1706 from the cutter proximal end 1722 and from the cutter distalend 1724 (the longitudinal ends of the convex cutting-edge profile1790). The midpoint 1792 also coincides with a turning point 1994 of theconvex cutting-edge profile 1790, which is a point at which the profileturns along the horizontal axis as seen in FIG. 17B. The turning point1794 of the convex cutting-edge profile 1790 is also a radiallyoutermost point of the convex cutting-edge profile 1790 relative to thelongitudinal axis 1706. In this example embodiment, the midpoint 1792,the turning point 1794, and the flat surface indexing feature 1726 allcoexist at the midpoint 1728 (D/2, a.k.a. the exact center) between thecutter proximal end 1722 and the cutter distal end 1724.

The body 1712 likewise defines a convex body profile 1796. In thisexample embodiment, the convex body profile 1796 defines an arcuateshape that forms a minor circular arc, although any shape is possible.The convex body profile 1796 is uninterrupted except for a lonesubregion 1798 defined by the recess 1720. The flat surface indexingfeature 1726 bisects the convex cutting-edge profile 1790 and the convexbody profile 1796. Along the longitudinal axis 1706, a profile of therecess 1720 is asymmetric about the midpoint 1792. As shown in FIG. 17B,asymmetric about the midpoint 1792 means that the part of the profile ofthe recess 1720 above the midpoint 1792 is not a mirror image of a partof the profile of the recess 1720 below the midpoint 1792. In thisexample embodiment, the part that is not symmetric is limited to thesubregion 1798.

FIG. 18A to FIG. 18C are various views of an example embodiment of aconvex shaper head 1808 with an example embodiment of an indexingfeature 1826. The convex shaper head 1808 operates using the sameprinciples as the concave shaper head 1608 of FIG. 16A, mutatismutandis. The convex shaper head 1808 is suitable for use with a shaperspindle 1304 like that shown in FIG. 13C to form a shaper head assembly.

The convex shaper head 1808 defines a longitudinal axis 1806 that whenassembled to the shaper spindle 1304 is the same as the longitudinalaxis 1306 of the shaper spindle 1304. The convex shaper head 1808includes multiple cutters 1810, a body 1812, a bore 1814 to secure thecutters 1810 to the shaper spindle 1304, multiple recesses 1820, acutter proximal end 1822, a cutter distal end 1824, the indexingfeatures 1826, a body proximal end 1840, and a body distal end 1842 thatis opposite the body proximal end 1840. While multiple cutters 1810 areshown, there only needs to be one cutter 1810. Likewise, while multiplerecesses 1820 are shown, there only needs to be one recesses 1820. Ifmultiple cutters are used, where each cutter occupies a different spacealong the longitudinal axis, then the cutter proximal axial end is theproximal end of the most proximal cutter and the cutter distal end isthe distal end of the most distal cutter.

The indexing feature 1826 is a flat surface that extends perpendicularto the longitudinal axis 1806 such that the normal line 1832 to the flatsurface extends parallel to the longitudinal axis 1806. The flat surfaceindexing feature 1826 is located at a midpoint 1828 (D/2, a.k.a. theexact center) between the cutter proximal end 1822 and the cutter distalend 1824.

Along the longitudinal axis 1806 the cutter 1810 defines a convexcutting-edge profile 1890. In this example embodiment, the convexcutting-edge profile 1890 defines an arcuate shape that forms asemicircle, although any convex shape is possible. The convexcutting-edge profile 1890 is symmetric about a midpoint 1892 of theconvex cutting-edge profile 1890. As shown in FIG. 18B, symmetric aboutthe midpoint 1892 means that the part of the convex cutting-edge profile1890 above the midpoint 1892 is a mirror image of a part of the convexcutting-edge profile 1890 below the midpoint 1892. However, the convexcutting-edge profile 1890 need not be symmetric about the midpoint 1892.

The midpoint 1892 is a point that is equidistant along the longitudinalaxis 1806 from the cutter proximal end 1822 and from the cutter distalend 1824 (the longitudinal ends of the convex cutting-edge profile1890). The midpoint 1892 also coincides with a turning point 1994 of theconvex cutting-edge profile 1890, which is a point at which the profileturns along the horizontal axis as seen in FIG. 18B. The turning point1894 of the convex cutting-edge profile 1890 is also a radiallyoutermost point of the convex cutting-edge profile 1890 relative to thelongitudinal axis 1806. In this example embodiment, the midpoint 1892,the turning point 1894, and the flat surface indexing feature 1826 allcoexist at the midpoint 1828 (D/2, a.k.a. the exact center) between thecutter proximal end 1822 and the cutter distal end 1824.

The body 1812 likewise defines a convex body profile 1896. In thisexample embodiment, the convex body profile 1896 defines an arcuateshape that forms a semi-circle, although any shape is possible. Theconvex body profile 1896 is uninterrupted except for a lone subregion1898 defined by the recess 1820. The flat surface indexing feature 1826bisects the convex cutting-edge profile 1890 and the convex body profile1896. Along the longitudinal axis 1806, a profile of the recess 1820 isasymmetric about the midpoint 1892. As shown in FIG. 18B, asymmetricabout the midpoint 1892 means that the part of the profile of the recess1820 above the midpoint 1892 is not a mirror image of a part of theprofile of the recess 1820 below the midpoint 1892. In this exampleembodiment, the part that is not symmetric is limited to the subregion1898.

As has been disclosed above, the router bits and indexing featuresdisclosed herein provide a quick, simple, and effective way ofaccurately aligning cutters of router bits with edges of workpieces in away not previously possible. Consequently, this represents animprovement in the art.

While various embodiments of the present invention have been shown anddescribed herein, it will be obvious that such embodiments are providedby way of example only. Numerous variations, swapping of features amongembodiments, changes, and substitutions may be made without departingfrom the invention herein. Accordingly, it is intended that theinvention be limited only by the spirit and scope of the appendedclaims.

The invention claimed is:
 1. An apparatus, comprising: a cutting bitcomprising a router bit or a shaper cutter head, comprising: a body; anda cutter secured to the body; wherein the cutting bit is installed in awoodworking machine the body is configured to rotate about alongitudinal axis; wherein along the longitudinal axis: the cutterdefines a concave or convex cutting-edge profile; the cutting-edgeprofile is symmetric about an axial midpoint of the cutting-edge profilethat is equidistant from longitudinal ends of the cutting-edge profile;and the cutting-edge profile comprises a turning point at the axialmidpoint; and wherein the body comprises a recess that defines a flatindexing surface that is disposed at the axial midpoint, that protrudesradially outwards from a portion of the body, and that defines a normalline that is parallel to the longitudinal axis.
 2. The apparatus ofclaim 1, wherein the cutting bit comprises the router bit, the apparatusfurther comprising a router bit shank secured to the router bit.
 3. Theapparatus of claim 1, wherein the cutting bit comprises the shapercutter head, the apparatus further comprising a shaper spindle.
 4. Theapparatus of claim 1, wherein the cutting-edge profile comprises aconcave cutting-edge profile.
 5. The apparatus of claim 4, wherein theconcave cutting-edge profile comprises a semi-circle.
 6. The apparatusof claim 4, wherein the concave cutting-edge profile comprises a minorcircular arc.
 7. The apparatus of claim 1, wherein the cutting-edgeprofile comprises a convex cutting-edge profile.
 8. The apparatus ofclaim 7, wherein the convex cutting-edge profile comprises asemi-circle.
 9. The apparatus of claim 7, wherein the convexcutting-edge profile comprises a minor circular arc.
 10. An apparatus,comprising: a cutting bit comprising a router bit or a shaper cutterhead, comprising: a body; and a cutter secured to the body; wherein thecutting bit is installed in a woodworking machine the body is configuredto rotate about a longitudinal axis; wherein along the longitudinal axisthe cutter defines an arcuate cutting-edge profile; wherein the arcuatecutting-edge profile comprises a midpoint that is equidistant fromlongitudinal ends of the arcuate cutting-edge profile, wherein relativeto the longitudinal axis the midpoint is a radially inner most or aradially outermost point on the arcuate cutting-edge profile; andwherein the body comprises a recess that defines a flat indexing surfacethat is disposed at an axial midpoint of the cutting-edge profile thatis equidistant from longitudinal ends of the cutting-edge profile, thatprotrudes radially outwards from a portion of the body, and that bisectsthe cutting-edge profile.
 11. The apparatus of claim 10, wherein themidpoint is disposed at a turning point of the arcuate cutting-edgeprofile.
 12. The apparatus of claim 10, wherein the cutting bitcomprises the router bit, the apparatus further comprising a router bitshank secured to the router bit.
 13. The apparatus of claim 10, whereinthe cutting bit comprises the shaper cutter head, the apparatus furthercomprising a shaper spindle.
 14. The apparatus of claim 10, wherein thecutting-edge profile comprises a concave cutting-edge profile comprisinga semi-circle or a minor circular arc.
 15. The apparatus of claim 14,wherein the concave cutting-edge profile comprises a bullnose profile ora thumb nail profile.